Dental caries, also described as “tooth decay” or “dental cavities”, is an infectious disease which damages the structures of the teeth. Dental caries can lead to pain and tooth infection. Dental caries often starts on the surfaces between adjacent teeth, also known as the approximal space. Proximal caries is one of the most common forms of caries.
The most common treatment of dental caries comprises the steps of excavating the tooth for removing the decayed part, this is usually done with a dental drill, whereafter a curing filling material is placed in the cavity to restore the function, integrity and morphology of the missing tooth structure.
When restoring a tooth it is of importance that the tooth returns to its original position in contact with the adjacent tooth and that the filling does not create what is called an overhang in the approximal space. An overhang is created if the dentist fails to seal off the preparation box, thus enabling the filling material to flow into the approximal space. The excess material creates an edge underneath the filling in which food remains can be trapped which usually leads to new dental caries or gingivitis.
Dental instruments have been used to close off a hole or trench made for the purpose of receiving a filling in a tooth. It is common knowledge that dentists use a shim or matrix, usually made of a metal or plastic material, to limit the flow of filling material to adjacent teeth and the approximal space. A second object when making a filling is to separate the teeth by placing a small tension on the teeth by means of a wedge. The placing of a small tension on the teeth allows the teeth to return to the original position, in which the teeth are in direct contact with each other, after the filling is completed.
Placing of a matrix band and achieving a good contact point after excavation for fillings is often a time consuming and pain staking procedure. Matrices of the past have generally had flat barriers that are held against the tooth and gums by small wooden or plastic wedges. The small loose wedges are difficult to handle and causes discomfort and pain. Furthermore, since the matrices of the past tend to be relatively inflexible and not anatomically shaped, they do not adequately seal against the tooth. The sharp metal matrix, when placed in direct contact with the gums, also creates cuts and discomfort. Thus, the wedge and matrix combinations of the past lack the ability to provide an adequate seal with the tooth, avoiding damage to the gums and providing a comfortable treatment for the patient.
Alternatives such as sectional matrixes in combination with retention are also very cumbersome and time consuming to place correctly. The tension created on the teeth from the tightening of the metal matrix as well as the sharp metal matrix being placed in direct contact with the gums of the patient creates pain and increases the risk of causing gingivitis during a dental procedure.